Preheat oven to 325°F.
Combine sauce ingredients in a food processor and purée to smooth. Place in a saucepot and gently simmer over low heat for 30 minutes to thicken and combine flavors.
For the burgers, soak bread in milk.
Place meats in a bowl and add seasonings, garlic, parsley, eggs, cheeses and olive oil, 2 turns of the bowl. Squeeze excess liquid from bread and crumble as you add it to meat. Combine meatball mixture and form 6 patties. Arrange on a baking sheet and roast 20-25 minutes to cook through.
Switch on broiler when you remove burgers from oven. Place rack at center of oven.